soc: arm: st_stm32: stm32f3: Add defines for I2C3
soc: arm: st_stm32: stm32f3: Add defines for I2C3

Add definitions for I2C3 which is present in some stm32f3 devices.

Signed-off-by: Galen Seitz <4b943fd5fb6f9590458eea94d3310f73210856ae@seitzassoc.com>

punitvara/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,nashif/zephyr,galak/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,explora26/zephyr,punitvara/zephyr,ldts/zephyr,punitvara/zephyr,nashif/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,nashif/zephyr,explora26/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,punitvara/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,nashif/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,explora26/zephyr,explora26/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr